Fix/mitigate bug #6722 (Linux: menu items cut/copy/paste not working) - To
avoid confusion, don't show Cut/Copy/Paste in HTML menu. They'll only work
in the native shell, with specially bound native menu items.
Merge pull request #8497 from adobe/pflynn/htmlmenu-noclipboard

Clear up bug #6722 (Linux: menu items cut/copy/paste not working)